The use of transplant tissues and organs in reconstructive and regenerative surgery is well-known. There are over 100 tissue banks currently in the U.S. that recover tissue from more than 25,000 donors and distribute in excess of 1.5 million allografts for transplant annually. However, the routine recovery of nerve tissue from cadaveric donors is a recent development in the tissue bank industry. Furthermore, recovery of nerve tissue, in particular lower arm nerve tissue, by minimally invasive procedures is not currently easily achieved.
Usually nerve tissue from a living donor or cadaver entails making large incisions in the body along the path of a nerve. In the case of a live donor, such large incisions are more prone to infections, tissue necrosis, swelling, scarring, poor healing, and long-lasting residual pain due to collateral tissue damage. Harvesting tissue from a cadaver is usually done soon after death and, obviously, before the body is embalmed. Thus, it can be important for aesthetic and other reasons to cause as little disruption or damage as possible to the body. The integrity of the cadaveric arterial system must especially be maintained so that the body can be properly embalmed. It can also be preferable to avoid disruption of the anatomical features as much as possible.
There are a variety of devices and tools that have been developed for obtaining donor tissues with minimal scarring and tissue disruption. For example, U.S. Pat. No. 7,320,687 discloses a “tendon stripper” and cutting device for harvesting tendons that requires a single, relatively small incision. A distal guide on the tendon stripper is placed around a donor tendon, or portion thereof, and gently pushed through the tissues with a rod, guided by the tendon. As it moves along the tendon, the distal guide pushes aside or “strips” by displacing and/or separating surrounding tissues from the donor tendon. After a sufficient length of tendon has been “stripped”, an electrical cautery wire on the device severs the end of the tendon within the body allowing the tendon to be removed from the body, leaving the surrounding tissues essentially intact and in place.
U.S. Pat. No. 7,163,547 discloses a device for harvesting veins from a body, in particular the saphenous vein in the upper leg. The tip end of this device is also inserted through an incision and placed around the end of a severed and tied vein. The tip end of the device is advanced through the leg tissues, guided by the vein. The end of the device has one or more cutting edges to separate the vein from surrounding tissues and/or sever branches therefrom. Once a sufficient portion of vein has been separated, the end of tip end is palpated to locate the tip end and the end of the donor vein. The vein at this site is tied and severed. The dissected portion of vein can then be removed from the body without avulsing surrounding or previously attached tissues or branches. An elongated needle can also be used to inject a local anesthetic during use.
While each of these devices is acceptable for their intended use, their designs and the designs of similar instruments, are not conducive to harvesting delicate nerve tissue. In fact, it has been documented that the use of tendon strippers, such as the one discussed above, often results in epineural nerve damage, as well as short or unpredictable nerve lengths. (Jaroszynski, G. and Johnston, G. H. F., “Harvesting of Sural Nerve with a Tendon Stripper”, 1996, Microsurgery 17:217-220.)